Search Results (225)

Aquaporins (AQPs) are membrane proteins that facilitate the transport of water and solutes. Among AQPs, plasma membrane intrinsic proteins (PIPs) play a critical role in maintaining water balance between the internal and external cell environments. This study focuses on the tomato due to its economic importance and cultivation under moderate salinity conditions in Japan. A swelling assay using X. laevis oocyte confirmed that all five examined tomato SlPIP2 isoforms showed water transport activity. Among them, two-electrode voltage clamp (TEVC) experiments showed that only SlPIP2;1, SlPIP2;4, and SlPIP2;8 transport Na⁺ and K⁺, with no transport activity for Cs⁺, Rb⁺, Li⁺, or Cl⁻. CaCl₂ (1.8 mM) reduced ionic currents by approximately 45% compared to 30 µM free-Ca²⁺. These isoforms function as very low-affinity Na⁺ and K⁺ transporters. Expression analysis showed that SlPIP2;4 and SlPIP2;8 had low, stable expression, while SlPIP2;1 was strongly upregulated in roots NaCl treatment (200 mM, 17days), suggesting distinct physiological roles for these ion-conducting AQPs (icAQPs). These data hypothesized that tomato icAQPs play a critical role in ion homeostasis, particularly under salinity stress. In conclusion, the first icAQPs have been identified in the dicotyledonous crop. These icAQPs are essential for plant resilience under salt stress. Full article

Soil salinity and sodicity are escalating global threats to agricultural productivity, severely limiting crop yield and quality. In the Igdir Plain of Türkiye, high summer temperatures, minimal precipitation, and a shallow groundwater table have intensified salinity-related challenges, currently affecting one-third of the arable land. Despite the substantial impact of salinity stress on eggplant (Solanum melongena L.) production, studies addressing plant tolerance mechanisms under real field conditions remain limited. In this study, eggplant was cultivated in eight distinct soil classes under open-field conditions to evaluate the effects of soil salinity and saline-alkalinity on morphological, physiological, and biochemical traits. Increasing soil exchangeable sodium percentage (ESP) and electrical conductivity (ECe) levels significantly suppressed plant height, root length, stem diameter, and leaf area, along with over 90% reductions in shoot and root biomass. Salinity impaired the uptake of essential nutrients (Ca, K, P, and Fe), while promoting toxic Na⁺ accumulation in leaves. This ionic imbalance induced oxidative stress, as indicated by elevated malondialdehyde (MDA), hydrogen peroxide (H₂O₂), and antioxidant enzyme activities (SOD, CAT, APX), all of which were strongly correlated with proline accumulation. The results highlight a coordinated plant response under salinity stress but also reveal the insufficiency of natural defense mechanisms under high salinity levels. Unless supported by external interventions to improve stress resilience and ensure productivity, growing eggplant in saline–alkaline soils should be avoided. Full article

Human embryonic stem cell-derived cardiomyocytes (hESC-CMs) tend to show a mixed population of action potential (AP) types, including atrial-like (A-like) and ventricular-like (V-like) APs. In the present study, we investigated the membrane currents underlying these two AP types in hESC-CMs. These were generated using standard (Std) and retinoic acid (RA)-based differentiation protocols. Patch clamp methodology was used to correlate AP morphology with major cardiac ion currents by applying alternating current and voltage clamp protocols to each cell, and to measure L-type Ca²⁺ current (I_Ca,L) and Na⁺-Ca²⁺ exchange current (I_NCX) in detail, whereas Ca²⁺ transients were measured ratiometrically using Indo-1. A- and V-like APs were found in both Std and RA-treated hESC-CMs and the AP plateau amplitude (AP_plat), as a measure of fast phase-1 repolarization, appeared the best AP criterion to separate these two AP types. Traditional voltage clamp experiments revealed a significantly smaller I_Ca,L density in RA-treated hESC-CMs, as well as larger densities of the transient outward and delayed rectifier K⁺ currents (I_to1 and I_K, respectively), without changes in the inward rectifier K⁺ current (I_K1). The AP_plat showed strong and moderate correlations with the densities of I_Ca,L and I_K, respectively, in the absence of a clear-cut correlation with the density of I_to1. Using pre-recorded, typical A- and V-like APs, AP clamp demonstrated that the I_Ca,L-mediated Ca²⁺ influx during the V-like AP in Std hESC-CMs is 3.15 times larger than the influx during the A-like AP in RA-treated hESC-CMs. Ca²⁺ transients of A-like hESC-CMs have a lower diastolic and systolic level, as well as a lower amplitude, than those of Std hESC-CMs, while their duration is shorter due to enhanced SERCA activity. In conclusion, I_Ca,L is an important determinant of the differently shaped A- and V-like APs in hESC-CMs. Furthermore, the Ca²⁺ homeostasis differs between A- and V-like hESC-CMs due to the smaller I_Ca,L and enhanced SERCA activity during A-like APs, resulting in a strongly reduced Ca²⁺ influx, which will cause a substantial reduction in I_NCX, further contributing to the shorter A-like APs. Full article

Plant functional traits serve as vital tools for understanding vegetation adaptation mechanisms in changing environments. As the primary organs for nutrient acquisition from soil, fine roots are highly sensitive to environmental variations. However, current research on fine-root adaptation strategies predominantly focuses on tropical, subtropical, and temperate forests, leaving a significant gap in comprehensive knowledge regarding fine-root responses in rocky-desertification habitats. This study investigates the fine roots of Pseudotsuga sinensis across varying degrees of rocky desertification (mild, moderate, severe, and extremely severe). By analyzing fine-root morphological and nutrient traits, we aim to elucidate the trait differences and correlations under different desertification intensities. The results indicate that root dry matter content increases significantly with escalating desertification severity. Fine roots in mild and extremely severe desertification exhibit notably higher root C, K, and Mg concentrations compared to those in moderate and severe desertification, while root Ca concentration shows an inverse trend. Our correlation analyses reveal a highly significant positive relationship between specific root length and specific root area, whereas root dry matter content demonstrates a significant negative correlation with elemental concentrations. The principal component analysis (PCA) further indicates that the trait associations adopted by the forest in mild- and extremely severe-desertification environments are different from those in moderate- and severe-desertification environments. This study did not account for soil nutrient dynamics, microbial diversity, or enzymatic activity—key factors influencing fine-root adaptation. Future research should integrate root traits with soil properties to holistically assess resource strategies in rocky-desertification ecosystems. This study can serve as a theoretical reference for research on root characteristics and adaptation strategies of plants in rocky-desertification habitats. Full article

B-raf (rapidly accelerated fibrosarcoma) is a crucial player within the ERK/MAPK signaling pathway. In the CNS, B-raf has been implicated in neuronal differentiation, long-term memory, and major depression. Mice with forebrain neuron-specific B-raf knockout show behavioral deficits in spatial learning tasks and impaired hippocampal long-term potentiation (LTP). To elucidate the mechanism(s) underlying diminished synaptic plasticity in B-raf-deficient mice, we performed whole-cell recordings from CA1 pyramidal cells in hippocampal slices of control and B-raf mutant mice. We found that the NMDA/AMPA ratio of excitatory postsynaptic currents (EPSCs) at the Schaffer collateral—CA1 pyramidal cell synapses was significantly reduced in B-raf mutants, which would at least partially account for their impaired LTP. Interestingly, the reduced NMDA component of field postsynaptic potentials in mutant preparations was partially reinstated by blocking the apamin-sensitive small-conductance Ca²⁺-activated K⁺ (SK) channels, which have also been reported to modulate hippocampal LTP and learning tasks. To determine the impact of B-raf-dependent signaling on SK current, we isolated the apamin-sensitive tail current after a strong depolarizing event and found indeed a significantly bigger SK current in B-raf-deficient cells compared to controls, which is consistent with the reduced action potential firing and the stronger facilitating effect of apamin on CA1 somatic excitability in B-raf-mutant hippocampus. Our data suggest that B-raf signaling readjusts the delicate balance between NMDA receptors and SK channels to promote synaptic plasticity and facilitate hippocampal learning and memory. Full article

Triple-negative breast cancer is the most aggressive subtype of breast cancer and is associated with the worst prognosis. Conventional chemotherapy remains the gold standard treatment for this disease but is associated with a high relapse rate, highlighting the urgent need for effective targeted therapies. The PI3K/Akt/mTOR pathway, dysregulated in nearly 60% of these cancers, appears to be a prime target. It involves a signaling cascade beginning with PI3K activation followed by activating phosphorylation of Akt and then mTOR complex, which activates oncogenic processes by enhancing protein synthesis, inhibiting apoptosis, dysregulating autophagy and promoting DNA repair that supports tumor cell survival. Moreover, the PI3K/Akt/mTOR pathway plays a central role in the development of chemoresistance. Numerous alterations (activating the mutation of PIK3CA or the loss of tumor suppressor PTEN) may lead to its overactivation. Targeted inhibitors of PI3K, Akt and mTOR have been developed to counteract this dysregulation. However, numerous cancer resistance mechanisms have emerged, reducing their efficacy, for example, reactivation of Akt following mTOR blockade, reactivation of the pathway by insulin signaling or activation of compensatory pathways such as the MAPK pathway, thus limiting their integration into routine practice. To counteract these resistances, combination therapies currently being investigated in clinical trials aim to improve clinical outcomes of PI3K/Akt/mTOR pathway inhibition. The aim of this review was to summarize current therapies developed to target this pathway in TNBC, with a focus on the resistance mechanisms that limit their effectiveness. Full article

Background/Objectives: Electrochemotherapy (ECT) is a reliable and potent technique for managing primary tumors; however, significant efforts are being made to characterize and improve the systemic immune response, which is crucial for metastasis prevention. Current evidence suggests that the advancement of ECT will depend on its integration with complementary immunomodulatory methods. Methods: In this study, we examined the combined effects of calcium-based electrochemotherapy (CaECT, 1.3 kV/cm × 100 µs, eight pulses delivered at 1 Hz repetition frequency) with dendritic cell vaccination (DCV). Lewis lung carcinoma (LLC1) was used as a tumor model. We characterized the effects of CaECT alone and in combination with DCV therapy on tumor growth, analyzed the changes in immune cell subpopulations, and studied the humoral immune response dynamics on day 10, 20, and 30. Given the limited effect of DCV, additional experiments were conducted with the chemotherapeutic drug cyclophosphamide (CP), known for its immunomodulatory properties. Results: Although CaECT demonstrated potent antitumor activity and induced a significant immune response, its combination with DCV did not result in enhanced therapeutic efficacy. The combination of CP also failed to improve median survival. Conclusions: It is concluded that CaECT is a promising alternative to standard ECT involving bleomycin or cisplatin. However, further optimization is necessary to enhance the therapeutic synergy of CaECT when combined with DCV. Full article

(1) Background: Osteonecrosis of the femoral head (ONFH), caused by insufficient blood supply, leads to bone tissue death. Current treatments lack effective bone regeneration materials to reverse disease progression. This study introduces an injectable and self-setting 3D porous bioceramic scaffold (Mg@Ca), combining MgO + SiO₂ mixtures with α-hemihydrate calcium sulfate, designed to promote bone repair through in situ pore formation and osteoinduction. (2) Methods: In vitro experiments evaluated human bone marrow mesenchymal stem cell (h-BMSC) proliferation, differentiation, and osteogenic marker expression in Mg@Ca medium. Transcriptome sequencing identified bone development-related pathways. In vivo efficacy was assessed in a rabbit model of ONFH to evaluate bone repair. (3) Results: The Mg@Ca scaffold demonstrated excellent biocompatibility and supported h-BMSC proliferation and differentiation, with significant up-regulation of COL1A1 and BGLAP. Transcriptome analysis revealed activation of the PI3K-Akt signaling pathway, critical for osteogenesis. In vivo results confirmed enhanced trabecular density and bone volume compared to controls, indicating effective bone repair and regeneration. (4) Conclusions: The Mg@Ca scaffold offers a promising therapeutic approach for ONFH, providing a minimally invasive solution for bone defect repair while stimulating natural bone regeneration. Its injectable and self-setting properties ensure precise filling of bone defects, making it suitable for clinical applications. Full article

Gliomas are the most common and lethal malignant primary brain tumors in adults, associated with the highest number of years of potential life lost. The latest WHO classification for central nervous system tumors highlighted the need for new biomarkers of diagnosis, prognosis, and response to therapy. The PI3K/Akt signaling pathway is clearly implicated in tumorigenesis, being one of the most frequently altered pathways in cancer. Activating PI3KCA mutations are oncogenic and can influence both prognosis and treatment response in various tumor types. In gliomas, however, studies have reported inconsistent PIK3CA mutational frequencies, ranging from 0% to 30%. Furthermore, the impact of these alterations on glioma diagnosis, prognosis, and therapy response remains unclear. Current evidence suggests that PIK3CA mutations may represent early and constitutive events in glioma development, associated with worse glioblastoma prognoses, earlier recurrences, and widespread disease. Among these, the hotspot mutation H1047R has been particularly associated with a more aggressive phenotype while also modulating the neuronal microenvironment. In this review, we examine the clinical relevance of PIK3CA mutations across different cancers, with a particular focus on their emerging role in glioma. Moreover, we also discuss the therapeutic potential and challenges of targeting PIK3CA mutations in the context of glioma. Full article

Phosphatidylinositol-3-kinase (PI3K)/AKT/mammalian target of rapamycin (MTOR) pathway hyperactivation is seen in a multitude of malignancies. Due to the importance of this pathway in numerous critical cellular functions, preclinical and clinical investigations have aimed to target this pathway as an anti-cancer therapeutic strategy. This has led to the development of PI3K, AKT, and MTOR inhibitors for use in cancer patients, leading to multiple FDA approvals over the past decade. In this review, we outline therapeutic targets in PI3K/AKT/MTOR signaling in solid tumors, the current state of using inhibitors of this pathway to treat patients whose cancers possess activating mutations in PIK3CA, AKT1/2, or MTOR, and exciting new inhibitors that are entering clinical trials. Full article

Indomethacin, ibuprofen, and acetylsalicylic acid (ASA) are non-steroidal anti-inflammatory drugs (NSAIDs) that inhibit prostaglandin (PG) synthesis. Previous studies in airway smooth muscle demonstrated that chronic exposure to testosterone (TES, 40 nM) enhances the relaxation induced by salbutamol and theophylline due to K⁺ channel increment, without modifying cyclooxygenase expression. This study examines how indomethacin, ibuprofen, and ASA affect K⁺ currents and the relaxation response to these bronchodilators. In organ baths, tracheas from young male guinea pigs chronically (48 h) treated with 40 nM TES showed increased relaxation to salbutamol and theophylline, which was completely abolished by indomethacin. Patch-clamp recordings revealed that TES increased salbutamol- and theophylline-induced K⁺ currents, and only indomethacin fully inhibited this potentiation; ibuprofen and ASA had partial effects. The involved currents included voltage-dependent K⁺ (K_V) and high-conductance Ca²⁺-activated K⁺ (BK_Ca) channels. Our results demonstrate that indomethacin exerts a dual action, inhibiting K⁺ channel activity and PG synthesis, unlike ibuprofen and ASA. This dual mechanism explains its stronger inhibitory effect on TES-enhanced ASM relaxation. These findings suggest that indomethacin may counteract the protective effects of TES, which promotes anti-inflammatory and smooth muscle-relaxing states. Therefore, it is advisable to exercise caution when prescribing indomethacin to young males with asthma, as the protective role of TES may diminish, potentially resulting in an exacerbation of asthma symptoms. Full article

Pituitary cells are specialized cells located within the pituitary gland, a small, pea-sized gland situated at the base of the brain. Through the use of cellular electrophysiological techniques, the electrical properties of these cells have been revealed. This review paper aims to introduce the ion currents that are known to be functionally expressed in pituitary cells. These currents include a voltage-gated Na⁺ current (I_Na), erg-mediated K⁺ current (I_K(erg)), M-type K⁺ current (I_K(M)), hyperpolarization-activated cation current (I_h), and large-conductance Ca²⁺-activated K⁺ (BK_Ca) channel. The biophysical characteristics of the respective ion current were described. Additionally, we also provide explanations for the effect of various drugs or compounds on each of these currents. GH₃-cell exposure to GV-58 can increase the magnitude of I_Na with a concurrent rise in the inactivation time constant of the current. The presence of esaxerenone, an antagonist of the aldosterone receptor, directly suppresses the magnitude of peak and late I_Na. Risperidone, an atypical antipsychotic agent, is effective at suppressing the I_K(erg) amplitude directly, and di(2-ethylhexyl)-phthalate suppressed I_K(erg). Solifenacin and kynurenic acid can interact with the K_M channel to stimulate I_K(M), while carisbamate and cannabidiol inhibit the I_h amplitude activated by sustained hyperpolarization. Moreover, the presence of either rufinamide or QO-40 can enhance the activity of single BK_Ca channels. To summarize, alterations in ion currents within native pituitary cells or pituitary tumor cells can influence their functional activity, particularly in processes like stimulus–secretion coupling. The effects of small-molecule modulators, as demonstrated here, bear significance in clinical, therapeutic, and toxicological contexts. Full article

Currently, developing cotton cultivation in saline–alkali soils is a vital focus for restructuring the cotton industry in China. The seedling stage, specifically the three-leaf stage, is a crucial period for assessing the salt tolerance of cotton. This research examined 430 natural populations of upland cotton, including 45 semi-wild germlines of Gossypium purpurascens. We measured the phenotypic responses of salt stress injury on seedlings as well as potassium (K), calcium (Ca), sodium (Na), and magnesium (Mg) concentrations in the roots, stems, and leaves following a 72 h exposure. The comprehensive salt tolerance index (CSTI) was determined using a membership function, principal component analysis, and cluster analysis based on 48 phenotypic traits related to salt tolerance. The results revealed significant variations in the phenotypic traits of the ion group under salt stress. Salt stress greatly affected the relative contents of Mg, K, and Ca ions in the aboveground parts of cotton, and correlations were observed among the 48 indices. The CSTI was calculated using seven principal component indexes, identifying 30 salt-tolerant, 114 weakly salt-tolerant, 39 salt-sensitive, and 4 highly sensitive materials based on cluster analysis. Among the 45 G. purpurascens cotton resources, 28 were weakly salt-tolerant, while 17 were salt-sensitive. Through TMT (Tandem Mass Tag)-based quantitative analysis, we identified 3107 unique peptides among 28,642 detected peptides, resulting in 203,869 secondary mass spectra, with 50,039 spectra successfully matched to peptides. Additionally, we identified several salt tolerance-related pathways (carbon metabolism; glutathione metabolism; the biosynthesis of amino acids, etc.) and proteins classified within the CAZy (Carbohydrate-Active EnZYme) family and expansin proteins. The results of this study concerning salt-tolerant materials provide a crucial theoretical foundation for the identification and evaluation of salt-tolerant breeding parents in cultivated cotton. Full article

Pulsatilla patens (L.) Mill. (Eastern pasque flower) is classified as a highly endangered and declining species in Europe. The present research assessed the current status of P. patens in Latvia by collecting data on its distribution in historical places, Natura 2000 territories, and other areas, largely covering the entire country. We aimed to analyze the relationships between P. patens populations size, demographic indicators, and soil parameters, in order to gain knowledge on the impact of local ecological factors and optimal growth conditions, which are important for conservation and potential reintroduction. Although P. patens was not detected in more than a third of the surveyed 624 locations, more than 18 thousand individuals were recorded. Our results indicate that optimal growth conditions for P. patens occurred near highways, forest roads, and paths, that is, in places with reduced competition from other species and improved lighting conditions. The seed viability ranging from 22% to 62% can be considered potentially sufficient for the continuation of the species if enough flowering plants and moss-free spaces for germination are maintained. Although P. patens tolerates a broad soil pH range, in Latvia this species mainly grows in acidic sandy soils with an average pH_KCl of 4.07. The soil parameters that most strongly positively correlated with P. patens regional population size and performance included higher soil pH level and plant available nutrient content, particularly P, K, Ca, Mg, Mn and B. Increased soil P and Mn levels significantly enhanced flowering, while high organic matter content could be associated with reduced population sizes. Despite its still large current population, long-term risks remain without active management. Conservation measures, such as creating open soil areas, where vegetation is removed and shading is reduced, are necessary to mitigate population decline. Full article

The expression level of Programmed Death-Ligand 1 (PD-L1) determined by the immunohistochemical method is currently approved to test the potential efficacy of immune-checkpoint inhibitors and to candidate patients with Non-Small Cell Lung Cancer (NSCLC) for treatment with immunotherapeutic drugs. As part of the CORELAB (New prediCtivebiOmaRkers of activity and Efficacy of immune checkpoint inhibitors in advanced non-small cell Lung cArcinoma) project, aimed at identifying new predictive and prognostic biomarkers in NSCLC patients receiving immunotherapeutic drugs, we investigated the role of circulating tumor DNA (ctDNA) molecular characterization as an additional predictive biomarker. We analyzed plasma ctDNA by targeted Next Generation Sequencing in a subset of 50 patients at different time points. ctDNA content was inversely correlated with the clinical outcome both at a baseline and after 2 months of treatment. OS was significantly higher in patients with ≥50% ctDNA reduction. TP53 and KRAS were the most frequently mutated genes, and patients with KRAS and/or TP53 mutations showed worse outcomes than patients without detectable variants or with mutations in other genes. Fewer common variants were found in BRAF, EGFR, MAP2K1, MET, NRAS, and PIK3CA genes. Our data demonstrated that molecular characterization of ctDNA and also its quantitative evaluation could serve as a dynamic, real-time prognostic, and predictive biomarker, enabling regular molecular monitoring of therapy efficacy in support of other medical examinations. Full article